The objective of this contract is to purify, isolate and characterize Luteinization Inhibitor (LI) from porcine follicular fluid (pFF). pFF provided by NIH will be evaluated to determine its content of LI and its suitability for use as the starting material for further purification. The production of a partially purified fraction, will permit independent verification of bioactivity and the evaluation of additional chromatographic procedures and the selection of the appropriate step(s) that will produce an "ultrapure" product suitable for characterization studies. Sufficient ultrapure product will be produced to permit the biochemical characterization of ultrapure LI and the production of a polyclonal antibody in rabbits suitable for use in immunoaffinity purification of LI. One sufficient partially purified material has been produced for final purification to the ultrapure form, the purification scheme for production of partially purified LI will be employed to produce material for distribution to the scientific community.